Glenn Ford, who spent nearly 30 years on death row in Louisiana for a murder he almost certainly did not commit, died on Monday in New Orleans, less than 16 months after his conviction and death sentence were vacated and he was released. He was 65.

William Most, a lawyer for Mr. Ford, said the cause was lung cancer, a diagnosis Mr. Ford received shortly after his release in March 2014. He died at a home provided by Resurrection After Exoneration, a nonprofit group that assists freed prisoners, Mr. Most said.

Mr. Ford walked out of the Louisiana State Penitentiary at Angola, one of the nation’s toughest prisons, after spending 29 years, 3 months and 5 days behind bars, nearly half his life, most of that time in solitary confinement for all but an hour a day.

After years of failed appeals, Mr. Ford’s extraordinary release was precipitated by “newly discovered and credible exculpatory evidence,” as prosecutors described it. In 2013, it was provided by a confidential informant to Dale G. Cox, then the first assistant district attorney and now the district attorney for Caddo Parish, which includes Shreveport.

It was there, on Nov. 5, 1983, that Isadore Rozeman, a frail 58-year-old with failing eyesight, was found shot to death in his small jewelry shop. Four men were initially accused of the murder, as well as the theft of jewelry, but Mr. Ford, who had done yardwork for Mr. Rozeman and was seen in the area of the shop on the day of the crime, was the only one who stood trial.

He was convicted largely on the basis of testimony by a witness, the girlfriend of one of the three other suspects, whose credibility was demonstrably undermined during the trial — she admitted to lying — and on circumstantial evidence. That evidence included a coroner’s claim that the fatal gunshot was likely fired by a left-hander.

That conclusion came despite the absence of a murder weapon, which was never found. And Mr. Ford was left-handed.

Also, Mr. Ford’s two court-appointed lawyers had scant experience in criminal law, and neither had ever presented a case before a jury. Mr. Ford was black, while the 12 jurors who convicted him and sentenced him to die — as well as the judge and Mr. Rozeman — were white.

Mr. Ford, 34 when the crime took place, had had drug problems but had no history of violence. He cooperated with the police investigation, acknowledging that he had been given stolen merchandise from the store by the other accused men and that he had pawned it, but denying that he was present when Mr. Rozeman was robbed and shot.

“Any exoneration is remarkable, of course,” the legal analyst Andrew Cohen wrote in The Atlantic on the eve of Mr. Ford’s release. “Any act of justice after decades of injustice is laudable. It is never too late to put right a wrong. But what also is striking about this case is how weak it always was, how frequently Ford’s constitutional rights were denied, and yet how determined Louisiana’s judges were over decades to defend an indefensible result.”

Mr. Ford was born in Shreveport on Oct. 22, 1949, and he had recently returned there from Riverside, Calif., where he and two siblings were reared by their mother’s mother. He went to school through the 11th grade and, Mr. Most said, at some point earned a high school equivalency diploma. For a time he went to cosmetology school.

He had returned to Shreveport, Mr. Most said, because he thought he needed a new start. There he lived with his father, whom he barely knew, and earned money doing odd jobs. For a time he worked at a sandwich shop.

He is survived by several children and more than 10 grandchildren, Mr. Most said.

In an interview, Mr. Cox said that the new evidence came to him while he was interviewing an informant regarding a different murder. To protect that source, and because the Rozeman case has been reopened, Mr. Cox would not identify the informant or disclose what he said. But the information he provided, Mr. Cox said, had been investigated and deemed credible and pointed to two brothers, Jake and Henry Robinson, who were among the original suspects. They are both in jail for other violent crimes.

In March, A. M. Stroud III, lead prosecutor at trial, wrote a remorseful article in The Shreveport Times, declaring, “Glenn Ford was an innocent man,” taking responsibility for a rush to judgment and arguing for the abolition of the death penalty.

“I apologize to Glenn Ford for all the misery I have caused him and his family,” Mr. Stroud wrote. “I apologize to the family of Mr. Rozeman for giving them the false hope of some closure. I apologize to the members of the jury for not having all of the story that should have been disclosed to them. I apologize to the court in not having been more diligent in my duty to ensure that proper disclosures of any exculpatory evidence had been provided to the defense.”

He concluded: “I end with the hope that providence will have more mercy for me than I showed Glenn Ford. But I am also sobered by the realization that I certainly am not deserving of it.”

Mr. Stroud said that Mr. Ford deserved compensation from the state for his wrongful conviction — he might have qualified for more than $300,000 under a Louisiana statute — though others were not so sympathetic. A district court judge, Katherine Dorroh, ruled that even though he was not the killer, he was guilty of possession of stolen goods, accessory after the fact to armed robbery and perhaps other crimes, and therefore not entitled to any payment.

And even though he was responsible for Mr. Ford’s release, Mr. Cox, who remains an ardent supporter of the death penalty, agreed with the judge that Mr. Ford “did not have clean hands in this matter.” In an interview, he was unwilling to say Mr. Ford was not guilty. “There was no exoneration,” Mr. Cox said. “There was new information that, had it been presented at trial, may have changed the verdict. It may not.

“I don’t know whether Glenn Ford was the shooter or not. I have my doubts. But that’s neither here nor there. I had to predict, in my mind, what 12 people would have thought of this information 30 years ago.

“Since I couldn’t be sure, I had to err on the side of caution. If it were me, I’d have changed my verdict, at least about the sentence.”

On the day he left Angola, Mr. Ford was asked what the conviction had cost him.

“Thirty years of my life, if not all of it,” he said. “I can’t go back and do anything I should have been doing when I was 35, 38, 40, stuff like that.”